Weight loss isn’t just about eating less and moving more. For many people, biology gets in the way. That’s where medications like Mysimba come in. But it’s not the only option. If you’re considering Mysimba, you’re probably wondering: are there better choices? Safer ones? Cheaper ones? Let’s cut through the noise and compare Mysimba - which combines naltrexone and bupropion - with the other weight loss medications actually available today.
Mysimba isn’t a single drug. It’s a fixed-dose combo of two FDA-approved medications: naltrexone and bupropion. Naltrexone, originally used for alcohol and opioid dependence, works on brain reward pathways. Bupropion, an antidepressant and smoking cessation aid, affects dopamine and norepinephrine. Together, they reduce cravings and make food feel less rewarding. The result? People eat less, not because they’re starving, but because the urge to snack fades.
In clinical trials, people on Mysimba lost about 5-8% of their body weight over a year - double what placebo groups lost. But it doesn’t work for everyone. About 1 in 3 people don’t lose even 5% of their weight, and side effects like nausea, headaches, and insomnia can make it hard to stick with.
If you’ve heard of Contrave, you’re not imagining things. It’s the same pill as Mysimba - same active ingredients, same doses, same manufacturer (Orexigen, now owned by Takeda). The only difference? Contrave is sold in the U.S., Mysimba in Europe and the UK. If you’re comparing Mysimba to other drugs, Contrave isn’t a real alternative - it’s the same thing with a different label.
So if you’re in the UK and seeing Contrave listed online as a "better option," it’s a red flag. It’s not better. It’s identical. Watch out for websites selling "American versions" - they’re just repackaging the same pills.
Saxenda is a daily injectable that mimics a gut hormone called GLP-1. It slows stomach emptying, tells your brain you’re full, and reduces appetite. It’s the same class of drug as Ozempic and Wegovy - but at a lower dose.
People on Saxenda typically lose 8-10% of their body weight in a year. That’s slightly more than Mysimba. It also works faster - noticeable changes often show up in the first 4-6 weeks. But there’s a catch: injections. Some people hate needles. Others get stomach cramps, nausea, or diarrhea. It’s also significantly more expensive than Mysimba, especially if you’re paying out-of-pocket.
If you’ve tried Mysimba and it didn’t work, or if you’re okay with injections, Saxenda is a solid next step. It’s not magic, but it’s more effective for most people.
Orlistat is the oldest weight loss pill still in use. It works by blocking fat absorption in your gut. About 30% of the fat you eat passes through undigested - which means you poop oil. Yes, really.
Weight loss with orlistat is modest: 3-5% over a year. But it’s cheap. You can buy Alli (the lower-dose version) over the counter at most UK pharmacies. No prescription needed. No brain chemistry changes. Just a lot of messy bathroom trips.
It’s not for everyone. If you eat a high-fat diet, you’re in for trouble. If you’re okay with eating low-fat meals and don’t mind the side effects, it’s a safe, low-risk option. But if you’re looking for real appetite control, this isn’t it.
Phentermine is a short-term appetite suppressant. It’s been around since the 1950s and still gets prescribed in the UK for up to 12 weeks. It works like a mild amphetamine - increases adrenaline, reduces hunger, boosts energy.
People lose 5-7% in 3 months. That’s fast. But the effects fade after a few weeks. It also raises blood pressure and heart rate. Not safe for people with heart conditions, anxiety, or a history of substance use.
It’s not a long-term solution. But for some, it’s a kickstart. Used with lifestyle changes, it can help break a plateau. But if you’re looking for something to take for months or years, phentermine isn’t the answer.
Metformin isn’t approved for weight loss in the UK - but doctors prescribe it off-label all the time, especially for people with prediabetes or PCOS. It doesn’t suppress appetite directly. Instead, it lowers insulin levels, which reduces fat storage and can lead to gradual weight loss.
Weight loss is slow: 2-5% over 6-12 months. But it’s safe, cheap, and has other benefits - like lowering blood sugar and improving fertility in women with PCOS. Side effects? Stomach upset, especially at first. But most people adjust.
If you’re insulin resistant or have metabolic syndrome, metformin might be a smarter choice than Mysimba. It’s not a magic weight loss pill, but it fixes the root problem for many.
There’s no one-size-fits-all. Your best option depends on your health, your goals, and your tolerance for side effects.
Also, consider this: none of these drugs work without lifestyle changes. Medications help. They don’t replace diet and movement. The best results come from combining them with regular exercise, protein-rich meals, and sleep.
Wegovy (semaglutide) and Ozempic (same drug, higher dose for diabetes) are the new gold standard. They’re GLP-1 agonists like Saxenda, but stronger. People lose 15-20% of their body weight on average. That’s huge.
But they’re hard to get in the UK. The NHS only prescribes them for people with type 2 diabetes or a BMI over 35 with related conditions. Private clinics charge £150-£300 a month. Supply shortages mean long waitlists.
If you can get Wegovy, it’s better than Mysimba. But if you can’t, Mysimba is still a valid, evidence-backed option. Don’t feel like you’re settling - you’re just working with what’s available.
| Medication | Common Side Effects | Severe Risks |
|---|---|---|
| Mysimba | Nausea, headache, constipation, dizziness, insomnia | Increased blood pressure, suicidal thoughts (rare) |
| Saxenda | Nausea, vomiting, diarrhea, stomach pain | Pancreatitis, gallbladder disease, thyroid tumors (in rodents) |
| Orlistat | Oily stools, frequent bowel movements, gas with discharge | Liver injury (very rare) |
| Phentermine | Dry mouth, insomnia, increased heart rate, anxiety | High blood pressure, heart valve damage (long-term use) |
| Metformin | Diarrhea, bloating, metallic taste | Vitamin B12 deficiency (long-term use) |
None of these drugs are risk-free. But Mysimba’s risks are generally lower than phentermine and comparable to Saxenda. The key is working with a doctor who monitors your blood pressure, mood, and liver function.
If you’ve tried Mysimba for 12 weeks and lost less than 5% of your weight, it’s unlikely to work better with time. The NHS recommends stopping if you haven’t seen results by then.
Don’t blame yourself. Weight loss meds aren’t one-size-fits-all. Your body’s chemistry just doesn’t respond to naltrexone and bupropion the way someone else’s does. That’s normal.
Next steps? Talk to your GP about Saxenda or metformin. Or try a structured lifestyle program. Sometimes, the problem isn’t the drug - it’s the lack of support. Group coaching, nutritionists, and behavioural therapy can make a bigger difference than switching pills.
Mysimba helps. So do the others. But none of them fix your relationship with food. None of them replace sleep, stress management, or movement. The most successful people aren’t the ones on the strongest drug - they’re the ones who combine medication with real, sustainable habits.
If you’re considering any of these options, start with your doctor. Don’t buy pills online. Don’t follow influencers. Get your blood work done. Talk about your history - depression, anxiety, heart issues, family history. The right choice depends on your whole story, not just your weight.
Yes, Mysimba and Contrave are identical in active ingredients and dosage. Mysimba is the brand name used in the UK and Europe; Contrave is used in the US. They are the same medication with different packaging and regional branding.
No. Mysimba affects brain chemistry, and combining it with stimulant-based supplements (like caffeine-heavy fat burners, garcinia cambogia, or appetite suppressants) can increase the risk of high blood pressure, anxiety, or seizures. Always tell your doctor about every supplement you take.
Most people notice reduced cravings within 2-4 weeks, but noticeable weight loss usually takes 8-12 weeks. Doctors recommend continuing for at least 12 weeks before deciding if it’s working. If you haven’t lost 5% of your body weight by then, it’s unlikely to work for you.
Mysimba is not routinely funded by the NHS for weight loss. It’s usually only prescribed privately or in specialist weight management clinics under strict criteria. Most people pay out-of-pocket, with a monthly cost ranging from £80 to £150 depending on the pharmacy.
Orlistat is generally the safest for long-term use because it acts only in the gut and doesn’t affect the brain. Metformin is also very safe for people with insulin resistance. Mysimba and Saxenda are safe for most people when monitored by a doctor, but they carry more potential side effects than orlistat.
I tried Mysimba for 3 months and lost 2 pounds. My doctor said it's 'working' because my cravings decreased, but I was just eating celery and crying. Why do we treat weight like a math problem when it's clearly a trauma response? 🤷♀️
Oh wow. Mysimba? How quaint. I mean, if you're still clinging to 2015-era pharmacology while the rest of us are on semaglutide cocktails and intermittent fasting podcasts, sure. But let's be real-naltrexone/bupropion is the pharmaceutical equivalent of using a flip phone in 2024. 📱➡️📱
You're not failing if Mysimba didn't work for you-you're just not the right fit for that combo. That's not weakness, that's biology. Try Saxenda or metformin. Or just start walking 20 minutes a day. Small steps, big changes. You got this 💪
Orlistat? LOL. You're telling me to eat 'low-fat meals' and accept oily butt explosions like it's some kind of spiritual cleansing? 😭 I'd rather swallow a live scorpion than poop grease for a year. Also, who wrote this? A pharmaceutical rep with a thesaurus and zero empathy?
